3) \(\frac{3}{4} + \frac{5}{7}\) = \(\frac{21}{28} + \frac{20}{28}\) = \(\frac{41}{28}\) = 1 \(\frac{13}{28}\)

3) \( \frac{3}{4} + \frac{5}{7} = \frac{3 \cdot 7}{4 \cdot 7} + \frac{5 \cdot 4}{7 \cdot 4} = \frac{21}{28} + \frac{20}{28} = \frac{21+20}{28} = \frac{41}{28} = 1 \frac{13}{28} \)